

Articles
by
V. Syzrantsev 
Total Records (
3 ) for
V. Syzrantsev 





V. Syzrantsev
,
K. Syzrantseva
and
A. Pazyak


The study considers the problem of loading capacity calculation of bevel precessional gear for pipeline valve drives. By nowadays spiroid gear and worm gear are the basis for industrial engineering of gearboxes. These gearboxes have a lot of disadvantages such as a low efficiency, significant starting torque and low reliability in cold temperature operating conditions. Researchers propose to use gearboxes based on bevel precessional gear. Bevel precessional gear is one of the progressive types of gears with a small shaft angle. Bevel precessional gears allow to increase the loading capacity, reliability and durability of gearboxes to reduce their cost and mass and dimension characteristics and to improve their efficiency and performance criteria. The study consider the problem of determination the loading capacity by the transmitted torque considering multiple contact of teeth and fixed value of the maximum contact stress allowed by the pinion and gear materials. Researchers solve the inverse problem of loading capacitytransmitted torque is calculated at a fixed number of tooth pairs in contact. The results of studying the bevel precessional gear enable to implement original methods of evaluation its loading capacity based on contact stress. 




V. Syzrantsev
and
K. Syzrantseva


The study considers the durability estimation task of details with complicated geometrical shape working in random regime at operation. The analytical dependences for stressstrain condition calculation of machines part and units do not exist, therefore estimation of the stresses and displacements of such objects is possible to carry out only by computer simulation with the help of numerical methods: Finish Element Method (FEM). External loads to details (pressure and temperature) are random values and generally aren’t described by known laws of distribution. Researchers have developed the original algorithm for estimation of probability of nofailure operation of details based on use of the apparatus of nonparametric statistics. Adjustment of nonparametric generators of random numbers is realized by methods of nonparametric statistics in accordance with real samples of pressure and temperature. As a result of realization of multiplefactor, computer experiment for calculation the stressstrain condition of detail under random loading the functions approximating the stress variation in dangerous points depending on the loads level are determined. On the basis of these functions, the estimation of probability of nofailure operation in all dangerous points of a detail is carried out. The algorithm developed by researchers is shown on the example of durability estimation (probability of nofailure operation) of the body of wedge valve KZ13010100. 





V. Syzrantsev
,
K. Syzrantseva
and
V. Ilyinykh


The study considers developed in kinetic theory of fatigue mathematical model for forecasting of stresscycled machine parts lifetime with specified probability of nondestruction. The results processing of samples fatigue tests is carrying out on a base of this model. Two parameters of this model: tensile strength and number of cycles before upper inflection point of lowcycle fatigue curve, related with tensile strength by nonlinear dependence are random values with unknown distribution laws. In that way left limits of confidence intervals of lowcycle fatigue curve, corresponding to specified probability (15%) of samples nondestruction used for forecasting of its lifetime are impossible to calculate. Researchers propose the original algorithm for model parameters determination of fatigue curve passing through any experimental point. Using this algorithm it is possible to calculate during computer modeling the set of fatigue curves. Obtained set of fatigue curves allows generating the random sample the number of cycles before destruction, for any fixed level of actual stress. This random sample is necessary for calculation of its quantile estimation at plotting of limits of confidence intervals. For regeneration of unknown density function of distribution this random value authors use mathematical apparatus of nonparametric statistics ensuring the task decision independently of complexity distribution law of researched random value. The results of developed algorithm realization are illustrated on example of limits of confidence intervals determination for results of lowcycle fatigue test of flexible pipes samples made of HS80 steel. 





